'''dict_a = {}
dict_b = dict()

dict_c = {'a':1,'b':2}
print(dict_c.values())  #结果：dict_values([1, 2])
print(dict_c.keys())    #结果：dict_keys(['a', 'b'])
print(dict_c.popitem()) #结果：('b', 2)  这个是被删除的键值对
d = {}
e = d.fromkeys([1,2,3,4])  #结果：{1: None, 2: None, 3: None, 4: None}
f = d.fromkeys(['a','b','c'],[1,2,3])   #结果：{'a': [1, 2, 3], 'b': [1, 2, 3], 'c': [1, 2, 3]}
'''

dict_tds = {i:i*2 for i in range(0,4)}
print(dict_tds)#结果：{0: 0, 1: 2, 2: 4, 3: 6}

